At present, security matters are being paid more and more attentions, and various public places are equipped with a variety of security inspection devices. Security inspectors may recognize dangerous objects from transmission images of objects to be inspected. The transmission images of an object to be inspected include two-dimensional and three-dimensional images, wherein the three-dimensional images are more recognizable than the two-dimensional images as problems caused by overlapping of the two-dimensional images along the thickness direction thereof may be eliminated. Usually, the imaging of a three-dimensional image of the object to be inspected is to revolve radiographic sources around the object to be inspected and to reconstruct an image of the internal structure of the object to be inspected by using transmission data from different angles of the object to be inspected.
Because of the complex structure of the equipment to revolve the radiographic sources around the object to be inspected, a linear scanning based imaging method is developed, in which the radiographic sources are fixed at one side of a scanning channel and the object to be inspected is moved relative to the radiographic sources along a broken line, and the transmission data of the object to be inspected from different angles are used to reconstruct the image of the internal structure of the object to be inspected.
However, the inventor of this application found that data in a cone angle direction of the radiographic sources is incomplete in the linear scanning based imaging method, which leads to existence of artifacts in the reconstructed image of the object to be inspected.